As I have described the history of vehicle manufacturing in these technical articles you will have noticed the close relationship between cars and aircraft – primarily because both industries were born around the same time and used similar components or materials. It was common for aircraft component manufacturers to re-use the technology for vehicle use.
Ground Effect was one of these concepts that crossed over. In an aircraft, Ground Effect and aerodynamics is used to keep the aircraft up in the air. For a vehicle it is the opposite, it pushes the car down on the ground causing better grip with the outcome of faster cornering.
So, it’s not surprising that these concepts were adopted by the motor sport manufacturers to get a competitive edge. The Chaparral car of the 60s was the first to sprout wings and other devices and they were quite flimsy but the concept wasn’t well known and the sport ultimately banned moveable devices on cars. Jim Hall who owned Chaparral used wings that moved up and down to adjust the downforce as the speed increased. It was important to keep the downforce equal at the front and back, so that grip was not compromised at either end.
Formula 1 in the late 60s saw a similar issue with flimsy wings as the materials used weren’t strong enough to provide the desired effect – carbon fibre and Kevlar were not available for use at this time.
So the designers started to look firstly at smoothing out the flow of air over and around the car by using wider side pods between the wheels and strategic but lower mounted wings to push the air away from the front.
By 1977, Lotus and Brabham were trying different ideas and it was Lotus that came out on top. The Brabham-Alfa BT46B used a large fan with skirts on the underside of the side pods that extracted the air from under the car. This car raced just three times before being dropped by Brabham’s owner Bernie Ecclestone. It did win the Swedish GP and showed that the concept provided masses amount of grip, so much so it was rumoured that when the car was idling it was sucked down on to the ground!
Lotus however used the side pods with radiators in them, skirts and a flat underside. Their 78 & 79 cars also had the pods styled to give better aerodynamics. Theses cars were championship winning designs.
One side effect was that if the “Ground Effect” was lost momentarily, the huge amount of grip was lost and the car would lose all steering control thus causing a bigger accident, and the flat bottoms acted as sails if the car managed to lift the front wheels too high. Remember the Mercedes Le Mans cars flipping at high speeds down the Mulsanne Straight.
The Ground Effect designs in F1 also changed as more works teams with big budgets used wind tunnels to add venturi tunnels and winglets to improve the stability of the cars as they change direction.
The work done by these teams can now be seen in road car designs where the designers use ideas first tested in F1 and Group C sports car racing to improve the aerodynamics and thus create a faster vehicle and reduced fuel consumption. The Bristol Fighter is a good example of this where the car actually increases power when driven faster and still has excellent fuel economy.